Problem: Christopher rode his bike for $8$ miles on each of the past $8$ days. How many miles did Christopher ride his bike altogether?
Explanation: The total number of miles biked is the product of the number of miles biked each day and the number of days that Christopher went biking. The product is $8\text{ miles per day} \times 8\text{ days}$ $8\text{ miles per day} \times 8\text{ days}= 64\text{ miles}$ Christopher biked a total of $64$ miles.